Saturn Capture & Processing question.

[asimov (John)]

Hi all.

To cut a long story short I'm having quite a time with Saturn. No matter what I try, 9 X out of 10 I end up with that problem of that 'ring on the globe' (see image below) My 1st Saturn I ever captured & put on site had this problem which was shot at 10 FPS with the toucam. It was recommended to me to shoot at 5 FPS to solve the problem. I've also read it's an under exposure problem.....& an over exposure one!! I've pretty well tried all setting combo's without really solving the problem.

My usual settings for Saturn are: 5 FPS / 1/25th sec exposure / brightness usually between 50 & 80% / Gain 40% on average / gamma zero.

Most nights I will take several AVIs of saturn @ 5/10 & even 15 FPS but the problem seems to be somewhat random, occuring on the 5 FPS AVI 50% of the time. I've thrown away some really good images of Saturn recently because of this

Is there any definite answer to this problem? Is this common? Is it perhaps a seeing condition problem...

Comments welcome.

[rumples riot]

From my own experience this is a under exposure problem. So you might need to increase the gain to 60%. This should fix the problem. Saturn is very hard to capture because of the low light at present. Must say I have always had problems with this planet.

[[1ponders] (Paul)]

I had exactly the same problem, though with Jupiter, never Saturn though. Check out these threads, they might give you some ideas to try

http://www.iceinspace.com.au/forum/showthread.php?t=887

http://www.iceinspace.com.au/forum/s...ead.php?t=1015

[asimov (John)]

Hey thanks for the feedback guys. Paul (1 ponders) It's interesting that in those threads you linked, the 'ring' was happening on jupiter rather than Saturn.

It could be a combination problem..ie: not enough gain (underexposure) coupled with the registax alignment box being too big. Hmmmm...It's given me some ideas, & I'll possibly try them out on Saturn in about 3.5 hrs (touch wood.)

BTW I've had this problem on Mars about 3 weeks ago, but only once. Also on jupiter once as well 2 weeks ago (which was going in the recycle bin in any case so no big deal)

Thanks again Paul & Paul!!

[[1ponders] (Paul)]

A couple more links that have a bit more info in them
http://www.iceinspace.com.au/forum/s...ighlight=Onion

http://www.iceinspace.com.au/forum/s...ighlight=Onion

[asimov (John)]

Ah yes! Thanks. At least I know what to call that problem now...the dreaded ONION RING EFFECT!!! Seems to be a common problem. I'll see if I can't nip this problem in the bud by being more particular with my capture settings, thanks again Paul.

[asimov (John)]

Just finished taking an AVI of saturn to test a few 'theories' out. I took it @ 10 FPS.

I wacked the gain upto 90% & kept the brightness at exactly 50% used the 64 alignment box in registax.

No 'onion rings' (yet)...